Flexible Solar Cells

Photo: Empa

The Previous Record was 17.6%

Scientists at Empa, the Swiss Federal Laboratories for Materials Science and Technology, have made flexible solar cells made of copper indium gallium selenide (CIGS) with a light-conversion efficiency of 18.7 percent, a new world record. This milestone, about 1% higher than the previous record, might seem like a small step forward, but when looked at in the context of constant incremental improvement, it is significative. What truly matters is the rate of improvement, and how it can be leveraged (1-2% multiplied by many gigawatts of capacity makes a huge different).

Photo: NREL

It’s all about money. To make solar electricity affordable on a large scale, scientists and engineers worldwide have long been trying to develop a low-cost solar cell, which is highly efficient, easy to manufacture and has high throughput. Now a team at Empa’s Laboratory for Thin Film and Photovoltaics, led by Ayodhya N. Tiwari, has made a major step forward. “The new record value for flexible CIGS solar cells of 18.7% nearly closes the “efficiency gap” to solar cells based on polycrystalline silicon (Si) wafers or CIGS thin film cells on glass,” says Tiwari. He is convinced that “flexible and lightweight CIGS solar cells with efficiencies comparable to the “best-in-class” will have excellent potential to bring about a paradigm shift and to enable low-cost solar electricity in the near future.” (source)

Flexible cells like these can be manufactured by ‘printing’ them with a roll-to-roll process, further reducing their cost, and because they are relatively light and flexible, they can be used in more places than the heavier and more rigid polycrystalline silicon cells.

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